This study aims to introduce a fluorescence-based chemosensing method for Zn2+ in aqueous suspens... more This study aims to introduce a fluorescence-based chemosensing method for Zn2+ in aqueous suspensions and untreated surface waters, conditions which generally hinder the application of conventional optochemical sensing platforms. A macrocyclic fluoroionophore was covalently bonded to a silica-coated magnetic nanoparticle and applied according to a predetermined protocol for analyzing trace amounts of Zn2+ under rarely investigated conditions. Utilizing the reversible complexation of the immobilized fluoroionophore, rapid regeneration was carried out via simple acidification after the magnetic-assisted solid-phase extraction of the particles. Forming inclusion complexes with Zn2+ with the receptor units of the particles leads to a significant enhancement in fluorescence intensity at 370 nm, above the detection limit of 5 ppb, with a dynamic linear range of quantification of 15–3000 ppb in a pH range of 5.5–7.5. Practical applicability was confirmed by analyzing untreated river water ...
A new phosphine-type potential secondary stabilizer was synthesized successfully with large natur... more A new phosphine-type potential secondary stabilizer was synthesized successfully with large natural raw material content. The stabilizer is a waxy white powder with a relatively low melting temperature. Both the thermal and the storage stability of the stabilizer are sufficient for practical use. The new stabilizer was introduced into a Phillips-type high-density polyethylene, and its stabilizing efficiency was determined by multiple extrusions. Commercial phosphite and phosphonite stabilizers were used as references. The additive packages contained a primary antioxidant and a phosphorus compound, both added at 1000 ppm. The chemical structure of the polymer, viscosity, color, and residual stability were determined after each extrusion. The comparison of the stabilizing efficiency of the three secondary antioxidants showed that the phosphine stabilizer is at least as efficient as the phosphorous secondary stabilizers available in the market. The new stabilizer proved to be the most ...
The metal ion and anion recognition abilities of the newly synthesized acridone derivative having... more The metal ion and anion recognition abilities of the newly synthesized acridone derivative having amide and ester groups were studied by UV–vis and fluorescence spectroscopies. The sensor molecule revealed selective recognition toward Ca(II), Hg(II), and fluoride in acetonitrile. Based on X‐ray crystallographic and 1H NMR analyses, intramolecular bifurcated H‐bond is formed between the acridone NH and the amide oxygens in the free receptor. Addition of Ca(II) and Hg(II) induced large fluorescence enhancements and changes in the 1H NMR shifts due to complexation, while fluoride deprotonated the sensor molecule giving rise to a new emission band. Selective sensing of Hg(II) based on absorption changes was also observed, presumably due to the tautomerization of the acridone unit upon complexation. The optical spectroscopic behavior in the presence or absence of Ca(II) and fluoride as chemical inputs provided an opportunity to construct IMP, INH, XOR, and XNOR molecular logic gates as w...
Rosenberg’s discovery of the antitumor activity of cisplatin represents the starting point to syn... more Rosenberg’s discovery of the antitumor activity of cisplatin represents the starting point to synthesize and study the antitumor and antibacterial activity of new Pt complexes. The aim of our research was to synthesize two types of platinum complexes containing glyoximes and amines, like [Pt(Glyox.H)2(amine)2] (Glyox.H2: Et-Bu-glyoxime, Me-pentyl-glyoxime, Et-Pr-glyoxime), and others formed with Schiff bases, [Pt(3-octanone)2(diamine)] (diamine: ethylene-, 1,2- and 1,3-propylene-, o-phenylene-diamine). After presenting the possible applications of these compounds, we report the study of their thermoanalytical behaviour (TG, DTA, DTG), spectroscopic features (such as FTIR, NMR, UV-VIS spectroscopies and also mass spectrometry) as well as their powder XRD. The antibacterial activity was also studied for different bacterial strains. Kivonat Rosenberg felfedezese a ciszplatin rakellenes hatasat illetően, kiindulo pontot jelentett uj Pt-komplexek előallitasara, es ezek daganatellenes, a...
Recycling of plastic materials has an important role in the twenty-first century in reducing envi... more Recycling of plastic materials has an important role in the twenty-first century in reducing environmental pollution and saving petroleum resources. Poly(ethylene terephthalate) (PET) provides one of the best examples for this as it is a non-biodegradable polymer that is mainly used as raw material for a wide range of packaging applications, making degradation of PET a subject of great interest for researchers. In our work, post-consumer PET bottles were degraded with glycolysis into bis(2-hydroxyethyl) terephthalate (BHET) monomer using commercially available functionalized silica gels or 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) immobilized on silica gel. After the most stable and active catalyst was found to be triethyl amine functionalized silica gel, the optimization of reaction parameters was carried out. The silica gel as solid support helps in recycling the applied organic base making this process sustainable. Kivonat A műanyagok ujrahasznositasa rendkivuli fontossagu a husz...
Dioximes as ligands are used as analytical reagents and serve as models for biological systems as... more Dioximes as ligands are used as analytical reagents and serve as models for biological systems as well as catalysts in chemical processes. A number of novel mixed complexes of the type [Fe(DioxH)2(amine)2] have been prepared and characterised by FTIR, 57Fe Mössbauer and mass spectroscopy by us. We have found strong Fe–N donor acceptor interactions and iron occurred in low-spin FeII state in all complexes. Later, we have also found that the incorporation of branching alkyl chains (isopropyl) in the complexes alters the Fe–N bond length and results in high-spin iron(II) state [1, 2]. The question arises: can the spin state of iron be manipulated generally by replacing the short alkyl chains with high volume demand ones in Fe-azomethine-amine complexes? To answer the question we have synthetized novel iron-bis-glioxime and iron-tris-gloxime complexes when long chain alkyl or aromatic ligands replaced the short alkyl ones and studied by 57Fe Mössbauer spectroscopy, MS, FTIR, UV-VIS, TG-...
A great number of biologically active compounds contain at least one amine function. Appropriate ... more A great number of biologically active compounds contain at least one amine function. Appropriate selectivity can only be accomplished in a few cases upon the substitution of these groups, thus functionalization of amines generally results in a mixture of them. The separation of these derivatives with very similar characteristics can only be performed on a preparative scale or by applying pre-optimized HPLC methods. A tris(pyridino)-crown ether was designed and synthetized for overcoming these limitations at a molecular level. It is demonstrated, that this selector molecule is able to distinguish protonated primary, secondary and tertiary amines by the formation of reversible complexes with different stabilities. This degree of substitution-specific molecular recognition of amines opens the door to develop separation processes primarily focusing on the purification of biologically active compounds in a nanomolar scale.
In this work, anchoring of cinchona derivatives to trifunctional cores (hub approach) was demonst... more In this work, anchoring of cinchona derivatives to trifunctional cores (hub approach) was demonstrated to obtain size-enlarged organocatalysts. By modifying the cinchona skeleton in different positions, we prepared four C3-symmetric size-enlarged cinchona derivatives (hub-cinchonas), which were tested as organocatalysts and their catalytic activities were compared with the parent cinchona (hydroquinine) catalyst. We showed that in the hydroxyalkylation reaction of indole, hydroquinine provides good enantioselectivities (up to 73% ee), while the four new size-enlarged derivatives resulted in significantly lower values (up to 29% ee) in this reaction. Anchoring cinchonas to trifunctional cores was found to facilitate nanofiltration-supported catalyst recovery using the PolarClean alternative solvent. The C3-symmetric size-enlarged organocatalysts were completely rejected by all the applied membranes, whereas the separation of hydroquinine was found to be insufficient when using organi...
Fluorescent chemosensors containing differently connected 1,2,3-triazole units for enantiomeric r... more Fluorescent chemosensors containing differently connected 1,2,3-triazole units for enantiomeric recognition studies of chiral protonated primary amines and amino acid esters.
This work presents the synthesis of six new phase-transfer organocatalysts in which the squaramid... more This work presents the synthesis of six new phase-transfer organocatalysts in which the squaramide unit is directly linked to the nitrogen atom of an aza-crown ether. Four chiral skeletons, namely hydroquinine, quinine, cinchonine (cinchonas), and α-d-glucopyranoside were responsible for the asymmetric construction of an all-carbon quaternary stereogenic center in α-alkylation and Michael addition reactions of malonic esters. We investigated the effects of these different chiral units and that of crown ethers with different sizes on catalytic activity and enantioselectivity. During extensive parameter investigations, both conventional and emerging green solvents were screened, providing valuable α,α-disubstituted malonic ester derivatives with excellent yields (up to 98%).
Acridino-diaza-20-crown-6 ether derivatives as new turn-on type fluorescent chemosensors with an ... more Acridino-diaza-20-crown-6 ether derivatives as new turn-on type fluorescent chemosensors with an excellent functionality and photophysical properties have been designed and synthesized for metal ion-selective optochemical sensing applications. Spectroscopic studies revealed that in an acetonitrile-based semi-aqueous medium, the sensor molecules exhibited a remarkable fluorescence enhancement with high sensitivity only toward Zn2+, Al3+ and Bi3+, among 23 different metal ions. Studies on complexation showed a great coordinating ability of logK > 4.7 with a 1:1 complex stoichiometry in each case. The detection limits were found to be from 59 nM to micromoles. The new ionophores enabled an optical response without being affected either by the pH in the range of 5.5–7.5, or the presence of various anions or competing metal ions. Varying the N-substituents of the new host-backbone provides diverse opportunities in both immobilization and practical applications without influencing the ...
: A chiral dimethylpyridino-18-crown-6 ligand was attached to silica gel by first forming an ally... more : A chiral dimethylpyridino-18-crown-6 ligand was attached to silica gel by first forming an allyloxy-substituted crown. This material was treated with triethyoxysilane and then coated and covalently attached to silica gel. This report shows the synthesis of the silica gel-bound chiral crown and its use in separating alpha-(1-naphthyl)ethylammonium perchlorate into its (R)- and (S)- forms.
This study aims to introduce a fluorescence-based chemosensing method for Zn2+ in aqueous suspens... more This study aims to introduce a fluorescence-based chemosensing method for Zn2+ in aqueous suspensions and untreated surface waters, conditions which generally hinder the application of conventional optochemical sensing platforms. A macrocyclic fluoroionophore was covalently bonded to a silica-coated magnetic nanoparticle and applied according to a predetermined protocol for analyzing trace amounts of Zn2+ under rarely investigated conditions. Utilizing the reversible complexation of the immobilized fluoroionophore, rapid regeneration was carried out via simple acidification after the magnetic-assisted solid-phase extraction of the particles. Forming inclusion complexes with Zn2+ with the receptor units of the particles leads to a significant enhancement in fluorescence intensity at 370 nm, above the detection limit of 5 ppb, with a dynamic linear range of quantification of 15–3000 ppb in a pH range of 5.5–7.5. Practical applicability was confirmed by analyzing untreated river water ...
A new phosphine-type potential secondary stabilizer was synthesized successfully with large natur... more A new phosphine-type potential secondary stabilizer was synthesized successfully with large natural raw material content. The stabilizer is a waxy white powder with a relatively low melting temperature. Both the thermal and the storage stability of the stabilizer are sufficient for practical use. The new stabilizer was introduced into a Phillips-type high-density polyethylene, and its stabilizing efficiency was determined by multiple extrusions. Commercial phosphite and phosphonite stabilizers were used as references. The additive packages contained a primary antioxidant and a phosphorus compound, both added at 1000 ppm. The chemical structure of the polymer, viscosity, color, and residual stability were determined after each extrusion. The comparison of the stabilizing efficiency of the three secondary antioxidants showed that the phosphine stabilizer is at least as efficient as the phosphorous secondary stabilizers available in the market. The new stabilizer proved to be the most ...
The metal ion and anion recognition abilities of the newly synthesized acridone derivative having... more The metal ion and anion recognition abilities of the newly synthesized acridone derivative having amide and ester groups were studied by UV–vis and fluorescence spectroscopies. The sensor molecule revealed selective recognition toward Ca(II), Hg(II), and fluoride in acetonitrile. Based on X‐ray crystallographic and 1H NMR analyses, intramolecular bifurcated H‐bond is formed between the acridone NH and the amide oxygens in the free receptor. Addition of Ca(II) and Hg(II) induced large fluorescence enhancements and changes in the 1H NMR shifts due to complexation, while fluoride deprotonated the sensor molecule giving rise to a new emission band. Selective sensing of Hg(II) based on absorption changes was also observed, presumably due to the tautomerization of the acridone unit upon complexation. The optical spectroscopic behavior in the presence or absence of Ca(II) and fluoride as chemical inputs provided an opportunity to construct IMP, INH, XOR, and XNOR molecular logic gates as w...
Rosenberg’s discovery of the antitumor activity of cisplatin represents the starting point to syn... more Rosenberg’s discovery of the antitumor activity of cisplatin represents the starting point to synthesize and study the antitumor and antibacterial activity of new Pt complexes. The aim of our research was to synthesize two types of platinum complexes containing glyoximes and amines, like [Pt(Glyox.H)2(amine)2] (Glyox.H2: Et-Bu-glyoxime, Me-pentyl-glyoxime, Et-Pr-glyoxime), and others formed with Schiff bases, [Pt(3-octanone)2(diamine)] (diamine: ethylene-, 1,2- and 1,3-propylene-, o-phenylene-diamine). After presenting the possible applications of these compounds, we report the study of their thermoanalytical behaviour (TG, DTA, DTG), spectroscopic features (such as FTIR, NMR, UV-VIS spectroscopies and also mass spectrometry) as well as their powder XRD. The antibacterial activity was also studied for different bacterial strains. Kivonat Rosenberg felfedezese a ciszplatin rakellenes hatasat illetően, kiindulo pontot jelentett uj Pt-komplexek előallitasara, es ezek daganatellenes, a...
Recycling of plastic materials has an important role in the twenty-first century in reducing envi... more Recycling of plastic materials has an important role in the twenty-first century in reducing environmental pollution and saving petroleum resources. Poly(ethylene terephthalate) (PET) provides one of the best examples for this as it is a non-biodegradable polymer that is mainly used as raw material for a wide range of packaging applications, making degradation of PET a subject of great interest for researchers. In our work, post-consumer PET bottles were degraded with glycolysis into bis(2-hydroxyethyl) terephthalate (BHET) monomer using commercially available functionalized silica gels or 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) immobilized on silica gel. After the most stable and active catalyst was found to be triethyl amine functionalized silica gel, the optimization of reaction parameters was carried out. The silica gel as solid support helps in recycling the applied organic base making this process sustainable. Kivonat A műanyagok ujrahasznositasa rendkivuli fontossagu a husz...
Dioximes as ligands are used as analytical reagents and serve as models for biological systems as... more Dioximes as ligands are used as analytical reagents and serve as models for biological systems as well as catalysts in chemical processes. A number of novel mixed complexes of the type [Fe(DioxH)2(amine)2] have been prepared and characterised by FTIR, 57Fe Mössbauer and mass spectroscopy by us. We have found strong Fe–N donor acceptor interactions and iron occurred in low-spin FeII state in all complexes. Later, we have also found that the incorporation of branching alkyl chains (isopropyl) in the complexes alters the Fe–N bond length and results in high-spin iron(II) state [1, 2]. The question arises: can the spin state of iron be manipulated generally by replacing the short alkyl chains with high volume demand ones in Fe-azomethine-amine complexes? To answer the question we have synthetized novel iron-bis-glioxime and iron-tris-gloxime complexes when long chain alkyl or aromatic ligands replaced the short alkyl ones and studied by 57Fe Mössbauer spectroscopy, MS, FTIR, UV-VIS, TG-...
A great number of biologically active compounds contain at least one amine function. Appropriate ... more A great number of biologically active compounds contain at least one amine function. Appropriate selectivity can only be accomplished in a few cases upon the substitution of these groups, thus functionalization of amines generally results in a mixture of them. The separation of these derivatives with very similar characteristics can only be performed on a preparative scale or by applying pre-optimized HPLC methods. A tris(pyridino)-crown ether was designed and synthetized for overcoming these limitations at a molecular level. It is demonstrated, that this selector molecule is able to distinguish protonated primary, secondary and tertiary amines by the formation of reversible complexes with different stabilities. This degree of substitution-specific molecular recognition of amines opens the door to develop separation processes primarily focusing on the purification of biologically active compounds in a nanomolar scale.
In this work, anchoring of cinchona derivatives to trifunctional cores (hub approach) was demonst... more In this work, anchoring of cinchona derivatives to trifunctional cores (hub approach) was demonstrated to obtain size-enlarged organocatalysts. By modifying the cinchona skeleton in different positions, we prepared four C3-symmetric size-enlarged cinchona derivatives (hub-cinchonas), which were tested as organocatalysts and their catalytic activities were compared with the parent cinchona (hydroquinine) catalyst. We showed that in the hydroxyalkylation reaction of indole, hydroquinine provides good enantioselectivities (up to 73% ee), while the four new size-enlarged derivatives resulted in significantly lower values (up to 29% ee) in this reaction. Anchoring cinchonas to trifunctional cores was found to facilitate nanofiltration-supported catalyst recovery using the PolarClean alternative solvent. The C3-symmetric size-enlarged organocatalysts were completely rejected by all the applied membranes, whereas the separation of hydroquinine was found to be insufficient when using organi...
Fluorescent chemosensors containing differently connected 1,2,3-triazole units for enantiomeric r... more Fluorescent chemosensors containing differently connected 1,2,3-triazole units for enantiomeric recognition studies of chiral protonated primary amines and amino acid esters.
This work presents the synthesis of six new phase-transfer organocatalysts in which the squaramid... more This work presents the synthesis of six new phase-transfer organocatalysts in which the squaramide unit is directly linked to the nitrogen atom of an aza-crown ether. Four chiral skeletons, namely hydroquinine, quinine, cinchonine (cinchonas), and α-d-glucopyranoside were responsible for the asymmetric construction of an all-carbon quaternary stereogenic center in α-alkylation and Michael addition reactions of malonic esters. We investigated the effects of these different chiral units and that of crown ethers with different sizes on catalytic activity and enantioselectivity. During extensive parameter investigations, both conventional and emerging green solvents were screened, providing valuable α,α-disubstituted malonic ester derivatives with excellent yields (up to 98%).
Acridino-diaza-20-crown-6 ether derivatives as new turn-on type fluorescent chemosensors with an ... more Acridino-diaza-20-crown-6 ether derivatives as new turn-on type fluorescent chemosensors with an excellent functionality and photophysical properties have been designed and synthesized for metal ion-selective optochemical sensing applications. Spectroscopic studies revealed that in an acetonitrile-based semi-aqueous medium, the sensor molecules exhibited a remarkable fluorescence enhancement with high sensitivity only toward Zn2+, Al3+ and Bi3+, among 23 different metal ions. Studies on complexation showed a great coordinating ability of logK > 4.7 with a 1:1 complex stoichiometry in each case. The detection limits were found to be from 59 nM to micromoles. The new ionophores enabled an optical response without being affected either by the pH in the range of 5.5–7.5, or the presence of various anions or competing metal ions. Varying the N-substituents of the new host-backbone provides diverse opportunities in both immobilization and practical applications without influencing the ...
: A chiral dimethylpyridino-18-crown-6 ligand was attached to silica gel by first forming an ally... more : A chiral dimethylpyridino-18-crown-6 ligand was attached to silica gel by first forming an allyloxy-substituted crown. This material was treated with triethyoxysilane and then coated and covalently attached to silica gel. This report shows the synthesis of the silica gel-bound chiral crown and its use in separating alpha-(1-naphthyl)ethylammonium perchlorate into its (R)- and (S)- forms.
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